DE2244908B2 - PERMSELECTIVE POLYMERIC MEMBRANES - Google Patents

Description

(1) the solution partially solidifies to such an extent that the obtained partially solidified membrane is self-sustaining or has self-sustaining properties, and

(2) the partially solidified membrane is immersed in a non-solvent d) for the linear polymer a) which is compatible with the organic solvent b), with at ^{least 5 at} least 75 percent by weight of the organic solvent b) or the organic solvent b) and the low molecular weight compound c) remaining in the partially solidified membrane are extracted.

3. The method according to claim 2, characterized in that the solution containing the three components a), b) and c) containing the low molecular weight compound c) in an amount which is less than 50 percent by weight, based on the linear polymer a), of the solution 7 to 50 percent by weight of linear polymer a) and the solution 50 to 93 percent by weight of organic solvent b) contains.

4. The method according to claim 2, characterized in that the partially solidified membrane with self-supporting property, which was prepared from the solution containing the components a) and b), preferably with the compound c) having a low molecular weight, into the non -Solvent d) is immersed at a temperature in the range from -20 ⁰ C to 50 ⁰ C, at least 80 percent by weight of the organic solvent a) or at least 80 percent by weight of each of the organic solvent b) and the low molecular weight compound c) extracted will.

50

The invention relates to permselective polymeric membranes for the selective separation of fluid mixtures, namely, permselective membranes containing a linear polymer that is N-aryl substituted Contains benzimidazole units, and a process for the preparation of such permselective membranes. It has long been known that specific components are separated in a fluid mixture, Can be purified or concentrated by reverse osmosis using a membrane or an interface with permselectivity is used.

Recently, reverse osmosis or reverse osmosis has been used Production of pure water from sea water or from salty water or other impure waters or by treating waste water and drainage more prominently, as an increasing There is a need for the safety of water supplies or resources and there is pollution should be avoided and as little energy as possible should be used.

The separation processes in which the permselectivity of such membranes is used has on the Areas of dialysis, electrolytic dialysis and ultrafiltration with great developments brought himself. Research has been undertaken with the aim of finding suitable substrates for such To create membranes and methods of making such membranes are available too place.

The quality of such permselective membranes is the most important factor in the separation process, where a reverse osmotic membrane is used, and to deal with membranes of this type To achieve effective separation, it is imperative that the membrane have a characteristic Has permselectivity.

The membrane should have such a characteristic that it enables a specific liquid medium in a fluid mixture flows through them, but that the others Components cannot penetrate. Will a separation using such a Membrane carried out, this must have a high mechanical strength that is sufficient to the high Operating pressure, and it must also be sufficient! practical penetration speed The membrane must also have the ability to produce these desired properties for a longer period of time. It is required that the membrane chemically and physically is stable for a long time under the operating conditions.

With the increasing importance of reverse osmosis separation processes, many attempts have been made to To develop substrates that are suitable for such membranes with the desired properties and various membrane substrates were tried. These common membranes show however, not high permeability or high desalination activity even when used for demineralization or desalination of sea water or saline water can be used, and their stability is not so high that it can be used on an industrial scale for a long time. It has been assumed that of the known membranes an asymmetrical cellulose acetate membrane, which is described by Lοeb and Sourirajan (see. US Pat. No. 3,133,132), which best is. However, a cellulose acetate membrane of this type is used under acidic or alkaline conditions or easily hydrolyzed by microorganisms or the like, causing deterioration in properties brings with it. It therefore only has a limited useful life. In addition to this The disadvantage is their limited use. Cellulose acetate membranes of this type are therefore not satisfactory.

Recently, permselective membranes using a nitrogenous polymer, such as a substrate, have been used completely aromatic polyamide or polyhydrazide, contain, described (see, for example, the US- ' Patent 135 67 632).

Typical examples of polymers containing nitrogen and described in this US patent

are, for example, polymetaphenylene-isophthalamide-tcrcphthalamide copolymers and polyisophthaloyl hydrazide. Although this reference describes that the benzimidazole ring in a chain of aromatic polyamides is not taught that nitrogen-containing linear polymers which contain N-aryl-substituted benzimidazole compounds in the main chain are suitable as substrate polymers for plastic polymeric membranes.

The subject of the invention are pcrmselective polymeric membranes which have an excellent permeability and which have the permeability of Allow water in an aqueous solution at high speed, but the dissolved substances not let through. The invention also relates to a method for producing such pcrmsclcktivcr membranes. These membranes also have excellent physical and chemical properties, such as Fesligkeil, Young's modulus, chemical stability and the like; they keep the excellent perkmselck civility during one under the operating conditions for a long time and can easily be manufactured from a substrate.

The pcrmselective polymeric membrane according to the invention is characterized in that

I. (I) the membrane consists essentially of a film-forming linear polymer, which as Main structural units of repeating N-aryl-substituted benzimidazole units (A) of the general formula

Means table group with up to 15 carbon atoms, trivalent in the formula A-I and in the Formula A-2 is representative, the two nitrogen atoms in each ring on two adjacent coal Substance atoms of the group Ar _{1 are} bonded, and Ar ₂ and Ar _{3 are} monovalent aromatic groups with up to 15 carbon atoms, the units of the formulas AI and / or A-2 directly or via divalent organic groups (B), in which

■ ο the average number of atoms excluding hydrogen atoms is not greater than 80, and wherein the two ends of the groups (B) bonded to the units (A) are carbon atoms are connected to each other;

(2) the parameter H _{p of} the hydrophilic property, expressed by the following formula, of the linear polymer is at least 0.4:

_{H =} N ₁₁ + ION,

^p Total number of atoms excluding

the hydrogen atoms in the polymer

and or

N N

• \ / V

—C Ar. C—

N N

I I

Ar ₃ Ar ₂

contains where Y is a group

—CONH—

—NHCO—

—CONHNHCO—

—NHCONH—

—NHCNHNHC—

(A-2)

and or

—C — NHNHCNH—

I! Il

ο ο

means, m represents zero or I, Ar, an aroma where N _{11 is} the number of hydrogen bonding units provided by the polar groups in the entire polymer and the product of the number (N _A ) of hydrogen bonding groups in the entire polymer and their hydrogen bonding strength (G _v ) and N _{1 represents} the number of ionic groups in the entire polymer, provided that the number of ionic groups does not exceed 1 per 500 units of the molecular weight of the polymer;

(3) the linear polymer in a solvent or solvent mixture, selected from Ν, Ν-dimethylacetamide, N-methylpyrrolidone, dimethylsulfoxide and / or hexamethylphosphoramide, which optionally contains up to 5 percent by weight of lithium chloride may contain rid, is soluble at 25 ° C to form an at least 7 weight percent solution; and

II. The membrane is made from a solution which contains

a) the linear polymer with an N-aryl-substituted benzimidazole structure and

b) an aprotic polar organic solvent, which has the ability to linear Dissolve polymers in it, preferably together with

c) a low molecular weight compound of not more than 500 which is soluble in the organic solvent b) and in the non-solvent d) below,

by

(1) the solution partially solidified to such an extent that the one obtained partially solidified

Membrane self-sustaining or self-sustaining Has properties, and

(2) place the partially solidified membrane in a non-solvent d) for the linear polymer a) immersed with the organic solution medium b) is tolerated, with at least 75 Ge weight percent of the organic solvent b) or of the organic solvent b) and the low molecular weight compound

c) remaining in the partially solidified membrane are extracted.

In summary, it can be said that the permselective polymeric membrane according to the invention has an S linear polymer containing as main structural units N-aryl-substituted benzimidazole units contains, the linear polymer meeting the following requirements:

(1) The linear polymer contains N-aryl-substituted benzimidazole units as main structural units of the following formula A-I

(A-I)

wherein m is 0 or 1, or of the following formula A-2

—C

Ar

Ar ₃

Ar,

C—

(A-2)

(2) The above-defined parameter (H _p ) of the hydrophilic property of the linear polymer is at least 0.4, preferably at least 0.5.

(3) The linear polymer has a certain degree of solubility (at least 7 percent by weight) in a solvent that mainly contains dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide or hexamethylphosphoramide (and the solvents being lithium chloride as a solubilizer in an amount not exceeding 5 percent by weight), and

(4) the linear polymer has a molecular weight sufficient to form films.

The above requirements (1) to (4) which the permselective polymeric membrane of the present invention meet must be described in more detail below.

1. Structure of the substrate polymer

As explained above, the above formula A can be written as follows:

When m in the above formula AI means I, the formula AI can be expressed as follows:

-Y-Ar ₁ C— Al / 1-

N
Ar ₂

and when m is 0, the formula A-1 is expressed as follows:

-Ar,

C—

A-1/2

N
Ar,

The divalent atomic group A can be represented by any of the above formulas A-I / 1, A-I / 2 or A-2 being represented.

I η of these formulas A-1 and A-2 or A-1/1, A-1/2 and A-2 / Lr ₁ denotes a trivalent or tetravalent aromatic group, and Ar ₂ and Ar ₃ denote a monovalent aromatic group ! table group. Each of these aromatic groups Ar ₁ , Ar ₂ and Ar ₃ contain up to 15 carbon atoms. Furthermore, these groups can be substituted by such substituents as lower alkyl groups, lower alkoxy groups, halogen atoms, nitro groups, sulfonic acid groups, carboxylic acid groups, lower alkoxycarbonyl groups or salts of these acid groups.

Y in the above formula denotes A-I or A-I / 1 a group of the following formulas

—CONH— (or -NHOC-)
—CONHNHOC-

—NHCONH -

—NHCNHNHC— / or —CNHNHCHN-

—C

Ar ₁

N
Ar,

and the number of group Y included in unit A

N is not particularly critical. In the

/ \ 55 Unit A can be one Y or can be two or more

C- (A-I) Y groups may be present.

\ / Atomic groups A represented by the above formulas

N A-1 and A-2 are expressed do not have to be the same,

I and two or more different radicals A can

Ar ₂ 60 be present in the polymer chain. The units

of A in the above formula A-I or A-2

N in the reverse manner as in formula A-I or

/ \ A-2 must be included.

C— (A-2) As mentioned above, B can either be an

/ 65 ply bond or a chain bond of the structural

N units to be A. Unit B can be any two

I be a valuable organic group if only the

Ar ₃ average number of atoms excluding the

609 524/389

Hydrogen atoms in the entire polymer chain is not greater than 80.

It is preferred that the subscript polymer as Unit A contains at least one of the groups represented by the following formulas:

N N

• \ / V

—C ArJ C—

N N

(IJ-I)

Ar ₃

Ar,

-Ar ₁ ' c— \ / N
I. I.
Ar ₂ N / V COHN-Ar; C-
\ /
N
I. Ar ₂

(11-2)

(Π-3)

/ \ -NHOC-Ar ₁ "C

Ar,

(11-4)

(V-a)

(V-b)

(V-C)

55

wherein R _{1 is} a hydrogen or a halogen atom or a lower alkyl group or lower alkoxy group with 1 to 3 carbon atoms, / 1 or 2 and Z is a single bond or an alkylene group with up to 4 carbon atoms, —O—, —S—, - SO ₂ - or --CO - means and, if Z represents a single bond, the formula Vc means a trivalent or tetravalent diphenyl group and "..." in the aromatic group represents a single bond in the case of Ar ₁ 'and a ίο

wherein Ar [and Ar ₂ 'denotes a group of the following formula:

Hydrogen atom or a substituent R ₁ in the case of Ai ['.

For the units B, it is preferred that the substrate polymer contains as units B: (I) at least one type of divalent organic groups, such as (i) aromatic hydrocarbon radicals which contain a benzene or naphthalene nucleus, (ii) aliphatic hydrocarbon radicals which contain a cyclohexane, cyclopentane or cyclobutane ring, (iii) straight-chain or branched, saturated or unsaturated hydrocarbon radicals with 1 to 6 carbon atoms and (iv) 5- or 6-membered heterocyclic radicals which contain oxygen or sulfur and which can be fused to a benzene ring , wherein carbon atoms are present in the terminal ends of the divalent organic groups, or (2) (a) at least one kind of divalent, trivalent or tetravalent organic groups, the carbon atoms being present in the two terminal ends and of the at ( i) to (iv) mentioned radicals originate, and (b) the organic groups with at least one kind of Bindegl lower, such as —O—, —S—, -SO ₂ -, —CO—,

—N—

(where R is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms or a phenyl group means),

—COHN—
—CONHNHOC—
0

Il

—NHCHN—

—CONHNHCOHN—

and

45

—C

—— ("* '

are bonded and wherein the atomic groupings (1) and (2) by a lower alkyl group with 1 to 4 carbon atoms, a lower alkoxy group having 1 to 4 carbon atoms, a .halogen atom, a Nitro group, an acid or carboxyl group, a salt of an acid residue, a lower alkoxycarbonyl group, a primary, secondary or tertiary amino

group, an ammonium salt thereof or a quaternary ammonium base may be substituted, and where in the units B present in the total polymer, the average number of atoms excluding the hydrogen atoms is not greater than 80, preferably not greater than 50.

The following are particularly preferred as substrate polymers: (I) Polymers in which the units A are at least

a kind of divalent groups, expressed by the following formula

Direction), —O—, —SO—, -CO

N—

—C

-CO

c—

(Vl)

(in this case the «or // ring is trivalent), ίο —CONHNHOC—, an alkylene group with I bis 4 carbon atoms,

are wherein Ar ₂ and Ar ^, which may be the same or different, are a monovalent aromatic group having up to 15 carbon atoms, expressed by the formula

Ν—

Il

—C

-N

Il

C-

(Vl-I)

20th wherein X is -O-, -S-, -NH-, or

—N—

(Vl-2)

30th means;

(II) Polymers in which the units A have at least one type of divalent atomic grouping which is represented by the following formula can be displayed,

(VI-3)

where R ₂ and R ₃ , which may be the same or different, denote a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, a halogen atom, a nitro group, a sulfonic acid or carboxylic acid group or a salt thereof, ρ 1 or 2 and Z has the definitions given above in formula Vc and wherein the units B have at least one kind of divalent organic group which is expressed by the following formula,

- (VIII-I)

or

- (VIII-2)

contain, wherein Ar _{2 has} the definitions given in the above formula VI, and the units B (VIi) 50 contain at least one kind of atomic groupings which are represented by the following formula,

where q _{x is} an average content of the units

60

which are contained in the polymer, and has a value of 0.2 to 3 moles per mole of the repeating units A, R ₂ and ρ have the definitions given above for the formula VI-I and W —CONH— (which also in opposite

where q _{2 is} the average content of the units

—W

and has a value of from 0 to 3 moles per mole

of the repeating units A and R ₂ , ρ and W have the definitions given in formulas VI and VII, and

(111) Polymers in which the units A represent at least one type of atomic groupings which are represented by the following formula X is expressed

C—

(X)

IO

wherein Ar _{2 has} the definition given above for formula VI, and the units B denote at least one type of atomic groupings represented by the following formula Xl

In Formula IV it is defined that N _{n means} the number of bonded hydrogen compounds provided by polar groups in the total molecule, expressed as the product of the number of hydrogen bonding groups (N _A ) in the entire polymer and their hydrogen bond strength (C ,,) and N _t mean the number of ionic groups in the entire polymer, with the proviso that the number of ionic groups does not exceed 1 per SOO in molecular weight of the polymer.

Methods for calculating the N _A , G ₁ , and N ₁₁ values are described in detail in references A and B cited above; Table I gives values of JV ₁ , G 1, and N ₁ , of typical polar groups .

Table I.

-r-W-4- -f

20 - Polar groups (XI)

Ketone, aliphatic-aromatic cr I. “Ether or diaromatic ether

N ₁ .

are expressed in which q ₂ , R ₂ , ρ and W have the definitions given above for formula IX.

2. Hydrophilic property

The substrate polymer used in the invention, which has the above-mentioned structure, has a hydrophilic parameter (H _p ) of at least 0.4, preferably at least 0.5. Polymers having a hydrophilic parameter (H ) of at least 0.55 are particularly preferred in the invention.

As mentioned above, the parameter (H _p ) of the hydrophilic property can be from the following formula

Dialiphatic ether 1

Amino, substituted amino I. or hydroxyl

Ester, sulfone or sulfoxide I, S

Amide 1.5

Imidazo I 1.5

Oxadiazole 2

C ₁ -2

4th 6th

2 4th 6th 4th

»Ρ =

N ₁₁ + ION,

Total number of atoms, excluding the hydrogen atoms in the polymer

(IV)

be calculated.

It is known that a polymer to be used as a substrate for permselective material, must be hydrophilic to some extent. The Para- The number of ionic groups in the total polymers, d. H. the / ν, value can easily be calculated from monomeric compounds that are used to make the substrate polymer. Typical cases of ionic groups in the Substrate polymers of the pcrmselective membrane according to the invention include —SO ₃ H, —SO ₃ Me (where Me is an alkali metal or an alkaline earth metal), —COOH, —COOMe (where Me is as defined above), an ammonium salt or a quaternary ammonium salt. It is preferred that the number of ionic Groups is 1 or less than 1 per SOO of the molecular weight of the substrate polymer.

meter N ₁₁ and N ₁ , which are used to calculate the

3. Solubility

meters (H _p ) of the hydrophilic property according to the formula Iv are used, for example, in the following references

A. Gordy, Stanford, Journal of Chemical Physics ", Vol. 9, pp. 204 to 214 (March 1941) and

B. U.S. Patent 3,567,632

described.

As can be seen from the above formula IV, the hydrophilic parameter (H _p ) of the polymer is given by the ratio of the sum of (i) the hydrogen bonding strength, based on various polar groups contained in the substrate polymer, and (ii) the number of ionic groups contained in the substrate polymer in terms of the number of the number of atoms excluding hydrogen atoms in the substrate polymer.

It is essential that the substrate polymer of the permselective polymer of the invention have the Requirement that the solubility at 25 ° C in a solvent containing at least one of the fol contains: Ν, Ν-Dimethylacet- amide, N-methylpyrrolidone, dimethyl sulfoxide and Hexamethylphosphoramide (the solvent may contain lithium chloride in an amount that Does not exceed 5%) at least 7 per cent by weight cent. It is preferred that the substrate polymer has a solubility value of at least 10 percent by weight.

It is not necessary that the substrate polymer have a solubility value of at least 7 weight percent based on all four solvents; it is sufficient that the polymer has a solubility value of at least 7 percent by weight on one of the four aforementioned solvents,

owns. Such a solvent can also use lithium chloride in an amount as a dissolving aid contain, which does not exceed 5 percent by weight.

4. Average molecular weight,

The substrate polymer of the permselective membrane of the present invention should have an average molecular weight (an average degree of polymerization) sufficient to form a film. To meet this requirement, it is preferable that the substrate is a polymer (/ _mfc *, determined at 30 ⁰ C) in veer te viscosity in a solution of the polymer in N-methylpyrrolidone at a concentration of 0.5 g / 100 ml of at least 0.4, especially at least 0.6.

5. Manufacture of substrate polymers

Process for the preparation of substrate polymers which meet the above requirements I to 4, are described in DT-OS 2244908, pp. 18 to 36.

6. Manufacture of membranes

The permselective membranes of the invention can be made by making a film forms a solution that mainly contains N-aryl-substituted benzimidazole homopolymers or copolymers, as previously described in an organic polar solvent.

Preferred solvents used to form the membranes are aprotic polar ones Solvents, especially so-called amide-like solvents such as N-methylpyrrolidone, N-methylcaprolactam, N, N-dimethylformamide, N, N-dimethylacetamide, hexamethylphosphoramide or tetramethylurea, and sulfone- or sulfoxide-like solvents such as dimethyl sulfoxide or tetramethylene sulfone. It is particularly preferred that such aprotic polar solvent be dielectric Has a constant (ε) of at least 1S.

When preparing a polymer solution using such a solvent as mentioned above, can include solubility, drying properties, solidifying properties and others Properties can be adjusted by adding a suitable diluent. As such a diluent are preferably used, for example: water, methanol, ethanol, chloroethanol, Ethylene glycol, chloropropanol, ethyl acetate or chloroform. It is preferred to have such a diluent is used in such an amount that the substrate polymer contained in the aprotic polar Solvent is dissolved, does not precipitate and that the film is its during the membrane forming step Does not lose transparency.

According to the invention, it is preferred to use a in the formation of the permselective membranes A method which consists in obtaining a solution comprising (a) a linear substrate polymer comprising the above-mentioned Contains N-aryl-substituted benzimidazole moieties, and (b) an aprotic organic Solvent, as noted above, which has the ability to affect the substrate polymer to dissolve, or a mixture of the solvents with a diluent, as indicated above (such Solvents and their mixtures are hereinafter referred to as "aprotic organic solvents" designated), and if desired together with (c) a compound of low molecular weight, both in the organic solvent (b) and in a non-solvent (d) which is im is mentioned below, is soluble and has a molecular weight not exceeding 500, partially solidified to such an extent that the resulting partially solidified product is "self-supporting" is), making the partially solidified product in (d) a nonsolvent for the linear substrate polymer immersed that is compatible with the polar organic solvent and wherein at least 75% by weight of the polar organic solvent (b) or of the extracted polar organic solvent (b) and from the low molecular weight compound (c) which remained in the partially solidified product. According to the invention, permselective membranes are obtained which have excellent permselective properties.

The preferred method according to the invention for producing the permselective membranes is now explained in more detail below.

According to the invention, the substrate polymer (a) which contains the above / anticipated repeating N-aryl-substituted Ienzimidazole units is dissolved in the aprotic organic solvent (b) in such an amount that the polymer concentration is about 7 to about 50 percent by weight, preferably about 10 to about 35 weight percent. Thus, a suitable amount of diluent, as mentioned above, can also be added before or after the dissolution of the substrate polymer. The dissolution of the substrate polymer in deni polar organic solvent is carried out at a suitable temperature within a range from room temperature to 100 ⁰ C.

Inorganic salts such as lithium chloride are preferably used in the dissolution of the substrate polymer, Lithium bromide, lithium nitrate, calcium chloride, calcium bromide, calcium nitrate or magnesium perchlorate, or organic compounds such as urea, ethylene glycol, glycerine or formamide. Inorganic Salts as noted above are considered to be low molecular weight compounds (c) particularly preferred. The dissolution of the low molecular weight compounds (c) in the aprotic polar solvent (b) can take place at any time. One can have such a connection low molecular weight (c) in the organic solvent (b) before, during or after dissolving the substrate polymer (a) in the solvent (b).

The solution thus formed, which contains the substrate polymer (a) and) the aprotic polar solvent (b) contains, optionally together with a low molecular weight compound (c), becomes partial solidified by separating a part of the solvent therefrom and removing it in such Measure that the substrate polymer in the solution receives the self-supporting property and where a partially solidified membrane of the substrate polymer (a) is obtained.

It is preferred that such be partially solidified Membrane 200 to 25 percent by weight, in particular 150 to 50 percent by weight, of the aprotic polar Solvent (b) or solvent (b) and the low molecular weight compound (c), based on the substrate polymer (a), in the partially

609 524/389

17 18

contains solidified membrane. It is also preferable in each case to the solvent (b) and the compound

admits that the amount of low molecular weight compound (c) when this

Molecular weight, which is contained in the starting solution before in the solvent (a), extracted and

handcn is, less than 50 percent by weight, separated from the partially solidified membrane,

particularly 5 to 30 percent by weight, based on the 5 It is preferred that this extraction in such

Substrate polymers. Extent takes place that 80 to 100 percent by weight

The preferred temperatures for the partial solvent remaining or 80 to

Drying, whereby a partially solidified mem- loo weight percentage of the remaining

bran obtained vary depending on the type of the solvent and the low compound

Solvent, the casting thickness, the drying time, io molecular weight can be separated. Man

the speed with which the air for drying receives such a permselcktivc, Mcm-

c, and other factors. But if bran.

the solidification according to the drying method Preferred examples of non-solvents (d),

takes place, preferred temperatures are in the range for immersing the partially solidified film

from 30 to 200 ^° C., in particular from 80 to 150 ^° C., or the membrane can be used

In the production of the abovementioned, in some cases, water, alcohols such as methanol, or ethylene-based membranes, it is possible to shape them into a suitable shape for nol, propanol, butanol, ethylene glycol or glycerol. For example, or aqueous solutions of such alcohols. The Verman the substrate polymer not only to a film turn of water, methanol, ethanol or a deform, you can also a thin coating of 20 aqueous solution of methanol or ethanol on a porous plate or on a substrate is particularly advantageous. In general, the exmatcrial or on hollow fibers etc. will form. If fraction formed preferably at a temperature in the bedic pcrmseleklive membrane as a film are run from -20 to +50 ⁰ C. If so, the above-mentioned solution is poured onto a tape or immersion extraction at too high a temperature a plate. If a porous substrate is carried out, although the extraction material is used, the speed of the substrate material can be accelerated, care must be taken with the solution, e.g. or transparency and immersion coated. If a membrane is to be formed on the bond of heterogeneous parts in the hollow fiber membrane, the solution 30 will be liable to deteriorate. Hollow fiber spinnerets are generally used for extrusion. One can perform the immersion extraction for a time so the above solution to partially solidified, sufficient that at least 75 weight sheets or membranes according to dry or percent of each remaining solvent wet method or with a combination and the low molecular weight compound of dry and process using a moist method. 35 from the partially solidified film or the partially

According to the invention, the partially solidified membrane thus formed will be removed. It is before-

Solidified product of the substrate polymer, which itself allows that after the extraction step the resulting

is bearing, immersed in a non-solvent (d), membrane is stored in water and this state

which is retained in the membrane with the aprotic polar organic solvent. In general

Solution (b) is compatible, but the substrate ₄₀ , the water content of the membrane is approximately

polymer (a) does not dissolve in it, and it is 25 to about 75 percent by weight,

at least 75 percent by weight of the remaining lo- The water content of the membrane is determined according to the

sungsmittcls (b) or at least 75 percent by weight calculated from the following equation:

,, .... Weight of the water contained in the membrane, “.

Water content (%) = ^ - ₇ -r τη; -R · 100.

Weight of the wet membrane

In some cases, when the membrane with hot namely a double-layer structure, which is a

Water from 70 to 95 ⁰ C after the immersion extract 50 dense upper layer and a thin, relatively porous

tionstufc is treated, the properties that layer contains. For example, you can use the

like the desalination ability, can be further improved. Process in which the moist film is formed,

When in the invention the connection with first only one film surface in contact with the low molecular weight (c) in the solution of the nonsolvent (d), and in doing so, becomes on Substrate polymer (a) in the aprotic polar 55 this side accelerates the degree of solidification. in the organic solvent is present, in the case of the dry method, solution immersion is used the partially solidified membrane in medium, preferably from a membrane surface the non-solvent (d) not only evaporates the organic, and while part of the solvent Solvent (b), but also the compound still remains in the membrane, becomes the membrane low molecular weight (c) extracted and immersed 60 in the non-solvent (d) to obtain the separated from the partially solidified membrane. to remove residual solvents and the like. As a result, permeable membranes are obtained in the case where it is necessary, a connection with very fine porous structure, thereby adding the perm low molecular weight (c), d. H. Selectivity of the membrane is further improved. an inorganic salt or an organic salt

As in the case of cellulose acetate membranes, 65 or an organic compound that differs from

See US Patent 31 33 132, the crfindungs- the organic solvent, based on the

according to substrate polymers in a permselective mem- average size and the evaporation

bran with asymmetrical structure can be deformed, speed, differentiates, the permselective

did the resulting membrane be greatly improved, by removing such a low molecular weight compound (c) in the extraction step.

The permselective membrane according to the invention generally has a thickness of 2 to 400 μ. In the event that the membrane is in the form of a sheet, the thickness of the membrane 10 to 400 μ, preferably 40 to 200 μ. The hollow fiber generally has an outer diameter of 20 to 150 microns, one Thickness of 5 to 40 µ and a void ratio (vacancy ratio) of 0.1 to 0.6.

The permselective membrane according to the invention can are easily manufactured, and it shows good water permeability and salting properties when they are used for the desalination or demineralization of sea water and salty water according to the reverse osmosis process is used. The membrane made of the substrate is atpolymeren chemically very stable and has excellent mechanical properties. It can be used for a very long time and even under high pressure, it shows good dimensional stability, and water permeability becomes only slightly diminished. The permselective membrane according to the invention therefore has a very large one practical value.

When the permeable membrane of the present invention is used for desalination or demineralization of sea water or salty water by the reverse osmosis method, it exhibits such excellent permselective properties that the water permeability Wp is 5 to 1300 l / m ² / hour. • atmosphere, and the salt retention rate is 40 to 99.8%. The water permeability and the salt retention capacity are determined according to the following formulas:

... .... .. ... amount of water that has penetrated (1),

Water permeability Wp = 10 ³ ,

Membrane area (m ² ) ■ time (hours) ■ pressure (atmosphere)

Salt retention capacity = 1 -

Salt concentration in permeated water

Concentration of salt used as feed material

! gnu n
igsmä

When determining the water permeability Wp according to the above formula, the pressure (atm) means the actual reverse osmosis pressure, ie (/ Ip- In), where Vp is the difference in the hydraulic pressures across the membrane and I.- τ means the difference in osmotic pressures across the membrane. ,

The permselective membrane according to the invention clearly differs from the membrane mentioned above US Pat. No. 3,567,632. The substrate polymer of the permselcktivcn according to the invention Membrane contains N-aryl-substituted groups in the main chain, and due to the presence of the The groups according to the invention have N-aryl-substituted groups permselective membranes have a high permselectivity, which is better than that of permselective membranes Membranes according to US Pat. No. 3,567,632. From the following examples it can be seen that a Comparison of poly (metaphenylene-isophthalamide / terephthalamide) copolymers, a typical example of a substrate polymer according to the US patent with the polyamide-benzimidazole used according to the invention! shows that the polymer used according to the invention is more easily processed into a membrane can be. The permeability properties, especially the permselective permeability, a membrane formed from the polymers of the invention is significantly better than that of a membrane made from the polymers of the US patent.

The permselective membrane according to the invention is effectively used not only for the desalination or demineralization of seawater or salty water, but also for the treatment of toxic waste water emitted from paper mills or pulp mills, plating works and similar plants, for the separation of radioactive waste water from nuclear reactors or the like, and for the separation or concentration of various components in the pharmaceutical, biochemical or food industry. The permselective membrane of the present invention can also be used in dialysis and electrolytic dialysis and is widely used in other fields.
The following examples illustrate the invention without, however, restricting it.

example 1

35

a) Preparation of the polymer

According to the method, as described in US Patent No. 35 18 234, a polyamide having a inherenien viscosity of 0.85 (determined at 30 ⁰ C as a solution of 0.5 g polymer in 100 ml of N-Methylpyrrolidpn; in The following are the values of the inherent viscosity, unless otherwise stated, determined in this way) prepared from terephthaloyl chloride and 2,4-diaminodiphenylamine by polycondensation using a methyl ketone water system. The polyamideimine was treated at 280 to 300 ° <p for 3 hours in a nitrogen atmosphere, a polyamide benzimidazole having an inherent viscosity of 1.93 being obtained. It was found by IR adsorp-

so tion spectral analysis that the conversion to the Polyamide-benzimidazole was more than 95%, and this polymer had repeating units of the following formula

55

60

The hydrophilic parameter (Hp) of the polymer was found by calculation to be 0.65. If the Nr / s value of this polymer according to the

21 22

in the US patent (writing 35 67 632 described Vcr water ^{treated at 80 0} C for 5 minutes was calculated, it was found that the value above and then in the same way as described above was 12, and that dropped Was the front side (the surface, polymers no longer in the scope of the US during the membrane sealing in the patent specification. 5 vapor the solvent in contact with air

was, the back means the surface cnt-

b) Production according to the invention of the membrane gcgcngcsctzt the front side) attached so that it

limited the side of the high pressure solution.

This polyamide-benzimidazole was in N-Mc- so the amount of water penetrating was 3.0 l / m ² /

thylpyrrolidone dissolved, so that the polymer concentration io hours, i.e. H. the level of restraint was 98%,

(ration IS was weight percent, and then and the water permeability was 570. Was the

Lithium chloride dissolved therein in an amount from the back of the solution kitc with high pressure

20 percent by weight, based on the weight of the polymer. set, the amount of penetrating water was

The resulting solution was dissolved at a micro-3.2 l / m ² / hour, the salt retention capacity was 94%,

Filter filtered and at a thickness of 60 μ on a 15 and the water permeability was 610.

smooth glass plate at room temperature by means of a. For comparison, a copolyamide with a

Cast squeegee. The poured material had a viscosity of 1.60 out of 100 mole percent

dried for 15 minutes at 130 ° C and then m-Phcnylcndiamin, 30 Mol% Tcrephthaloyl-

in methanol at 30 ⁰ C for about 30 micloride and 70 mol percent isophthaloyl chloride through

grooves immersed together with the glass plate. 20 Solution polycondensation at low temperature

The film was made peeled from the glass plate using an N-methylpyrrolidone system

and in a large amount of water at room temperature according to the method described in US Pat.

pcralurcine immersed long night. The various procedures used. Then became a

The membrane produced in this way was transparent, 15% by weight solution of the copolymer

and looked dark brown. The thickness of the membrane 25 in N-methylpyrrolidone, the 20 percent by weight Li

bctrug 33 to 36 μ, and the water content was thium chloride based on the weight of the polymer,

56%. A portion of the resulting membrane was prepared. From this solution one formed

cut, dried and the atomic absorption a colorless semitransparent membrane with a

subject to analysis. The amount of thickness was found to be from 40 to 44 μ, using the above bc-

Real lithium chloride was less than 0.003%. 30 different drying and immersion conditions

The wet membrane was used in reverse.

Osmosis device was used, which in particular was so constructed that it was able to withstand a pressure of up to 150 kg / cm ² permeability test at a pressure of 6.0 kg / cm ² . The area of the membrane was 11.3 cm ² . Using a 0.105% saline solution, a support with a pore size of 35 was obtained. When the front side used the 5μ side of the solution that bounded a sintered stainless steel with high pressure, the water bleed and filter paper was included. The membrane must be 2.2 l / m ² / h, the salt retention capacity was so attached that the surface area that was used for the 28%, and the water permeability was 420. The first stage of the membrane production during drying, the back of the membrane became the solution side was in contact with air exposed to the high pressure solution side, the water high pressure was adjacent. A saline solution with an inflow of 2.5 l / m ² / hour, the salt retention capacity at a concentration of 0.105% (with an osmo was 9.4%, and the water permeability was 477. Table pressure of 0.75 atm, determined at 25 ° C) This membrane was also hot was used in the permeation test, the water of 8O ⁰ C for 5 minutes, treated at 25 ⁰ C and a pressure of 6.0 kg / cm ² transit 45 and tested in the same manner as above . Has been led. the front of the solution page with high pressure

The amount of water exposed through the membrane, the water flow rate was 1.0 l / m ² /

permeated was determined periodically, and the hours, the salt retention was 50%, and the

The salt concentration of the permeated water, the water permeability Wp, was 190.

was conductometrically determined to be arranged around the salt side in such a way that it was the solution side with

can be determined. It was found that the high pressure was limited, the water flow

Result that the water passage 5.4 l / m ² / hour. flow 1.65 l / m ² / hour, the salt retention capacity bc-

bctrug and that the salt retention was 95%, 41%, and the water permeability was Wp

and the water permeability Wp was 1030,314.

The above experiment was repeated in the same way

fetches, with the exception that the surface that begins with _R. · 1 ?

had been in contact with air, so arranged e 1 s ρ 1 e I
was that she was the side with the high pressure solution

limited. It was found that the amount of water obtained by the same procedure as that used in the two permeation was 6.0 l / m ² / hr. When the salt retention was described in Game 1, a copolyamide property was 93.5%, and the water permeability of benzimidazole with a hydrophilic parameter Hp Wp was 1140. It is easily seen that the m of 0.61 and an inherent viscosity of 1.45 this example produced a good membrane made from 100 mole percent terephthaloyl chloride, 80 mole percent water viscosity and a high desalting percent 2,4-diaminodiphenylamine and 20 mole proactivity even at a pressure as low as 65 percent 4,4'-diaminodiphenyl ether.
6.0 kg / cm ² . This copolymer was then in N-methyl

A membrane which, in the same way as above, has dissolved pyrrolidone in such a way that the copolymer concentration

Bcschricbcn was produced with hot tion was 15 percent by weight. Calcium chloride

was then added and homogeneous in the solution in an amount of 20 percent by weight, based on the polymer weight, dissolved. From this solution, under the same conditions as in Example 1 described a membrane.

The resulting membrane had a thickness of 23 μ and a water content of 65.5%. As a result atomic absorption analysis found that the amount of calcium chloride contained in the membrane remained was 0.019%.

Using the same apparatus as in Example 1, the membrane was ^{subjected to the permeability test at a pressure of 6.0 kg / cm 2} using a 0.105% saline solution. When the front surface of the loosening cords was subjected to high pressure, the water flow rate was 6.47 l / m ² / hour, the water permeability Wp was 1230, and the salt retention was 93%. When the back of the solution side was subjected to high pressure, the permeating amount of water was 6.37 l / m ² / hour, the water permeability was 1,210, and the salt retention was 92%.

Example 3

The membrane examined had a thickness of f0 μ and a water content of 28%.

Example 5

A solution containing 15 parts by weight of the copolyamide-benzimidazole of Example 2, 4.5 parts by weight of lithium chloride and 80.5 parts by weight of N-methylpyr

was produced and marked with a rt, then the solution te poured to a thickness of 350 μ.

for 15 minutes at 130 ⁰ C, the casting immersed in water one day at room Rend. the

contained rolidon.

Microfilter filtri

on a Glaspia

One dried

and then became

temperature was

the resulting membrane had a thickness of 75 μ and a water content of 67%.

The membrane thus formed was in the same

Reverse osmosis apparatus as used in Example 1, and the permeability test was ^{carried out at Lg / cm 2} using the 1.0 weight percent of an inorganic as shown in Table 2 below. The results are also

25 ° C below 80
aqueous solution
Ganic salt
given, dwell

given in Table 2.

A 3.5% saline solution (with an osmotic pressure of 24.5 atm, determined at 25 ^° C.) was placed in the same reverse osmosis device that was described in Example 1. A membrane prepared in the same manner as described in Example 2 was attached thereto, and then the permeability test was carried out ^{at a pressure of 100 kg / cm 2.} When the face of the membrane was arranged to confine the high pressure solution side, water flowed in an amount of 27.3 l / m ² / hr. through, the water permeability was 362, and the salt retention was 97%. When the back of the membrane was attached to delimit the solution side with high pressure ^{, the water flow rate was 33.5 l / m 2} / hour, the water permeability was 445, and the salt retention was 89%.

Example 4

A 15gewichtsprozentige solution of the copolyamide-benzimidazole of Example 2 in N-Mcthylpyrrolidon was cast on a glass plate and dried at 100 ⁰ C for 3 minutes. The casting was then immersed in a 40% strength aqueous solution of calcium chloride at 100 ° C. for 10 minutes, a yellow semitransparent membrane being obtained.

After immersing in a large amount of water for 3 days, the membrane was ^{subjected to the reverse osmosis test at a pressure of 80 kg / cm 2} at 25 ° C. using a 3.5% saline solution. When the face of the membrane was attached to delimit the solution side with high pressure ^{, the water flow rate was 2.34 l / m 2} / hour, the water permeability Wp was 42, and the salt retention was 95%.

Table 2

Type of

inorganic

Salt

Water inflow

(l / m ² / hour)

Water salt

permeability retention capacity

CaCl ₂

LiNO ₃

NaNO ₃

Ca (NQj) ₂

14.0
17.5
16.0
15.8
14.3
16.5

195
244
222
220
185
230

Example 6

99.1

99.5

99.8

98.2

98.5

99.8

A solution which contained 6 g of the copolyamide-benzimidazole from Example 2 with an inherent viscosity of 1.45 and II, 8 g calcium chloride and 30 g N-methylpyrrolidone was poured onto a glass plate and at 130 ^° C. in air for 15 minutes dried. The casting was immersed in a large amount of water at room temperature together with the glass plate to remove residual solvent and calcium chloride therefrom. A membrane with a thickness of 28 μ was obtained in this way.

The membrane thus formed was used in the same apparatus as described in Example 1, and the permeability test was carried out under a pressure of 80 kg / cm ² using a 1.05% saline solution with the temperatures used as the feed material Solution, as indicated in Table 3, was varied. The results are also given in Table 3.

609 524/389

Table 3

srcs membrane thickness 0 ') after Feed solution temperature 50 "C Salt return KO ¹ C Salt back before use 25 ¹ C hallc- hallc- use of pressure Salt return water capital water be able to of pressure water Haltc- influx (%) inflow (%) inflow capital (%) (l / m ² / hour) (l / m ² / hour) (l / m ² / Sld.)

Copolyamide benzimidazole

28

Examples 7-20

15.5

96.6 33.8

92.0

45.5

88.5

The permeability of a plastic membrane can also be compared by direct osmosis a solution can be determined with an osmotic pressure. To show this, the following were made Tests carried out.

To a solution of N-Mcthylpyrrolidon, the Containing 15 percent by weight of the copolyamide-benzimidazole of Example 2, an inorganic one was added Salt or a low molecular weight compound as indicated in Table 4, in those listed in Table 4 indicated amounts, and the resulting solution was according to that described in Example I. Method potted into a membrane. The membrane thus formed was used as a diaphragm between Salt water with a concentration of 4.0 percent by weight (the osmotic pressure was 32.5 atm, determined at 25 ° C) and pure water used, and the water permeability rate and the salt permeation rate was determined at 25 ° C. The results are in Table 4 specified.

Table 4

Example no. Additive Lot**) Water content Thickness of the Water inflow Salt influx 0 the membrane membrane Art 1 (%) (/ ') ^ g / cm ² / sec) ^ g / cm ² / sec) 7th 2 18.4 13th 5.8 0.005 8th LiCI 5 21.8 5 10.0 0.010 9 LiCl 10 24.3 5 16.0 0.013 IO LiCI 20th 50.6 17th 57.0 0.015 Il LiCI I. 54.5 13th 150.0 0.100 12th LiCI 3 56.0 30th 295.0 0.125 13th CaCI ₂ 5 22.0 4th 7.4 0.085 14th CaCl ₂ IO 31.0 14th 12.4 0.053 15th CaCI ₂ 20th 37.0 5 44.3 0.094 16 CaCI ₂ 20th 46.0 18th 131.0 0.234 17th CaCl ₂ 15th 65.5 23 360.0 0.263 18th Mg (ClO ₄ ), 20th 21.2 21 8.3 0.003 19th urea 20th 24.3 18th 11.2 0.051 20th Glycerin 31.0 28 10.1 0.024 Comparison*) LiCI 42 86 0.93

*) Aromatic polyamide, produced in Example 1 as a comparative polymer, was used as the substrate polymer. **) The amount of additive was expressed by weight percent based on the weight of the polymer.

Example 21

A solution of Ν, Ν-dimethylacetamide, which contained a copolyamidimine in a concentration of 15 percent by weight, was prepared from 25 mol percent of phthaloyl chloride, 75 mol percent of isophthaloyl chloride, 80 mol percent of 2,4-diaminodiphenylamine and 20 mol percent of 4,4'-diaminodiphynyl ether, a solution polymerization in the presence of Ν, Ν-Dimcthylacetamid at low temperature carried out in the usual way. To the solution then were added Propylcnoxyd in an equimolar amount to the hydrochloric acid was in the solution, and the solution was heated for one hour at 100 ⁰ C to the copolyamide-imine to transfer benzimidazole copolyamide in the corresponding. According to the IR analysis, it was confirmed that cyclodehydration had occurred in the copolyamidimine. The resulting copolyamide-benzimidazole had an inherent viscosity of 0.71 and a hydrophilic parameter of 0.61.

The resulting polymer solution was divided into two parts. Lithium chloride became a part in one

Amount of 20 percent by weight based on the weight of the polymer was added. Then the two parts of the solution poured separately onto glass plates, dried at 115 ° C. for 15 minutes and immersed in methanol at room temperature together with the glass plate.

Using the membranes thus formed, the permeability test was carried out at 25 ° C and a pressure of 6.0 kg / cm ² using a 0.105% saline solution. Each membrane was placed so that the face delimited the side of the high pressure solution.

The membrane made from the lithium chloride-free solution (containing small amounts of hydrochloric acid, propylene oxide and propylene chlorohydrin) had a thickness of 15 μm and a water content of 25%. In the permeability test of this membrane, the inflow of water was 0.50 l / m ² / hour, the water permeability Wp was 95, and the desalination ratio was 98.5%.

The membrane which had been produced from the solution which contained 20 percent by weight of lithium chloride, based on the polymer, had a thickness of 18 μm and a water content of 54%. In the permeability test of this membrane, the water inflow was 3.8 l / m ² / hour, the water permeability Wp was 720, and the salt rejection was 97.6%.

B e i s ρ i e 1 22

According to the polymerization process described in Example 1, a polyamide-imine with the following structural units

--OCHN

NHCO

Π)

--0CHN

(2)

The NR / s values of the polyamidimine (1) were determined according to the method of the aforementioned U.S. patent 35 67 632 calculated, and it was found that this value was 6.5 and [the polyamide-imine thus below fell outside the scope of the US patent. The Nr / s value of the polyamide-benzimidazole (2) was calculated, and the WJ was found to be 12 and that the polymer (2) thus no longer came under the aforementioned US patent specification.

A solution containing 15 parts by weight of the polymer (1), 3 parts by weight of lithium chloride and 87 parts by weight of N-methylpyrrolidone was prepared. In a similar manner, a solution containing 10 parts by weight of polymer (2),
■ S and 87 parts by weight

made from 2,4-diaminodiphenylamine and isophthaloyl chloride.

Part of the polyamide-imine thus formed was subjected to cyclodehydration in the same manner as in Example 1 described, using a polyamide-benzimidazole with the following structural units

obtained in which greater than 95 percent by weight of the amidimine linkages were converted into amide-benzimidazole bonds.

3 parts by weight of lithium chloride contained N-methylpyrrolidone,

manufactured. Both Ljösungen were cast on a glass plate, immersed at 130 ⁰ C for 15 minutes, dried and resuspended in water at room temperature during one day.

The membranes thus obtained derived from the polymers (1) and (J2) were ^{subjected to the permeability test at 25 ° C and a pressure of 80 kg / cm 2} using the same reverse osmosis device as in Example 1 and employed a 1.0% saline solution. The results are shown in Table 5.

Table 5

35

40

Substrate polymer ι polymer Polymer with himself with himself again again fetching fetching A A units (2) units (1) (Ver equal sample) 52 Membrane thickness (μ) 48 65 Water content ( ¹ zo) 53 17.8 Water inflow rate 4.3 248 Water permeability Wp 60 98.6 Salt retention capacity (%) 92.1

It can be seen from the test results in Table 5 that the N-aryl-substituted benzimidazole bond the permselective properties greatly improved.

Example 23

According to the polymerization process described in Example 1, a copolyamide-benzimidazole was prepared from 80 mole percent 2,4-diaminodiphenylamine and 20 mole percent 3,3'-diaminodiphenyl sulfone. This polymer had a hydrophilic parameter H _p of 0.61.

In the same way as described in Example 1, a solution of the polymer in N-methylpyrrolidone was made at a polymeric concentration of 15 percent by weight, and was made therefrom made a membrane.

For comparison, a polyamide was made from 3,3'-diaminodiphenyl sulfone and terephthaloyl chloride

must follow the same procedure as described in Example 1 manufactured. This sample was used as a comparative polymer used. Using the polyamide thus formed, was carried out in the same manner as a membrane described above.

The two membranes produced in this way were subjected to the reverse osmosis test at 25 ° C. under a pressure of 80 kg / cm ² , using a 1.0% saline solution. The results are shown in Table 6.

Table 6

Subsidiary Polymcrcs 24 polyamide Copoly- (Comparative amide probc) benzimide azole 53 Water content (%) 61 50 Membrane thickness (μ) 53 17.6 Water inflow (l / m ² / hour) .32.8 244 Water permeability Wp 455 66.5 Salt retention capacity (%) 96.0 example

According to the polymerization process and the worm cyclodochydration process of Example 1, a copolyamide-benzimidazole having an inherent viscosity of 0.65 was prepared from 2.03 g (0.007 mol) of I, S-diamino ^ -dianilinobenzene, 0.324 g (0.003 mol) of methaphenylcinediamine and 2.03 g (0.01 mole) of isophthaloyl chloride were prepared. This polymer had a hydrophilic parameter H _p of 0.62.

Then 2.0 g of this polymer was homogeneously dissolved in a solution containing 20 g of N-methylpyrrolidone and 0.60 g of lithium chloride, and the resulting solution was poured onto a glass plate in a casting thickness of about 200 μ and placed in a dryer with a thermostat dried at 110 ^° C. until the amount of residual solvent was reduced to approximately 60%. Then the casting was immersed in a large amount of ion-exchanged water for one day.

The resulting membrane had a thickness of 45 μ and a water content of 56%.

Using the same reverse osmosis device as in Example 1, the reverse osmosis test of the membrane thus formed was carried out under the same conditions as described in Example 21. The water inflow was 20.8 l / n / hour, the water permeability Wp was 290, and the salt retention was 88%.

Examples 25 to 35

Polymers having the structural features shown in Table 7 were prepared according to the polymerization procedures described below, and membranes were prepared according to the conditions given in Table 8. The results the permeability tests for these membranes are shown in Table 9.

Process for the preparation of the polymers

(I) 70 mol percent 2,4-diaminodiphenylmethane and 30 mol percent m-aminobenzocic acid hydrazide were reacted with methyl haloyl chloride in N-methylpyrrolidone. The resulting polymer was precipitated in water and ^{stored at 300 0} C for 3 hours under reduced pressure, the gc-

desired polymers contained. The structure of the polymer was determined by infrared absorption analysis. The characteristic absorption lines of the oxadiazole ring at 1080 cm " ¹ and the characteristic absorption lines of

ίο N-substiluicrtcn imidazole rings were observed at 1320 cm " ¹ and 1380 cm" ¹ .

(II) A polymer was prepared by adding 70 mole percent 2,4-diaminodiphynylamine and 30 mole percent Isophthalyl dihydrazide with tcrephthaloyl chloride in the same "manner as described in (1) above implemented.

(III) A copolyamido-imine was prepared from 75 mole percent of phthaloyl chloride, 25 mole percent of fumaric chloride and 2,4-diaminodiphenylamine according to the interfacial polymerization method using a methylethylctone-water system, and then the resulting polyamidoamine in N-methylpyrrolidone was made into a small amount of N-methylpyrrolidone Hydrochloric acid contained dissolved, and then the solution was stirred for ^{2 hours at 120 0 C;} the desired polymer was obtained. The structure of the polymer was determined by IR analysis.

(IV) 80 mol percent 2,4-diaminodiphynylamine and 20 mol percent 2,4-diamino-4'-carboxydiphynylamine hydrochloride were polymerized with phthaloyl chloride in N-methylpyrrolidone. Calcium hydroxide was added to the resulting polymer solution in an amount sufficient to neutralize 95 percent of the hydrochloric acid present in the solution. The solution was then stirred for 2 hours at 120 ^° C., the desired polymer being contained.

(V) 20 mole percent 4-chloroformyl-N- (3-chloroformyl) phthalimide of the following formula

ClOC

COCl

80 mole percent tcrephthaloyl chloride and 100 mole percent 2,4-diaminodiphenylamine were polymerized and cyclodehydrated in the same manner as described in Example 1, and using a Polymeres received.

(VI) A polymer was prepared from 4- (2,4-diaminoanilino) diphenyl ether and terephthaloyl chloride according to the method described in Example 1 prepared.

(VII) A polymer was prepared by adding 70 mole percent 1,3-diamino-2,4-dianilinobenzene and 30 mole percent 3,3'-diaminodiphenyl sulfone with terephthaloyl chloride according to that described in Example 1 Procedure implemented.

(VIII) The polymerization and cyclodehydration were carried out in the same manner as in (IV) above carried out, with 75 mol percent l ^ -diamino ^ -dianilinobcnzol, 25 mol%

m-Aminobenzoc acid hydrazide and terephthalic acid chloride used. It was confirmed by IR analysis that under the cyclodehydration conditions used mainly the N-phenylbenzimiduzole ring was formed and LJm conversion of the hydrazide to the oxadiazotene ring hardly occurred.

(IX) According to the method described in "Journal of Polymer Science", 50, 511 (1961), the Melt condensation carried out, 70 mol% of 3-amino-4- (N-phenyI) -ammobenzoic acid methyl ester and 30 mole percent used methyl m-aminobenzoic acid.

(X) According to the examples of the US patent 33 89 122 method described was polyamideimine hydrazide prepared by adding 3-amino-4- (N-4-biphenyl) -aminobenzoylhydrazide reacted with terephthaloyl chloride in N-methylpyrrolidone. Calcium hydroxide was added to the resulting polymer solution in an amount sufficient to To neutralize 95% of the hydrochloric acid present in the solution. The solution then became Stored at 120 ° C. for 2 hours, the desired polymer being obtained.

PCI) The desired polymer was made, by adding 1,3-phenylene-2,2'-bis- [5-carboxy- (N-phenyf) -benzimidazole] the following formula

HOOC

COOH

polymerized with ^ '- Diphenylmethandiisocyanat at 160 to 18O ⁰ C in N-MethylpyrVolidon.

Table 7

Structural units and inherent viscosity of the polymers

Structural unit

'/ inc

- - OCHN

(70%)

(30%)

0.95

OCHN

(70%)

(30%)

1.13

OCHN

(75%)

--OCHN

(25%)

1.53

609 524/389

33

continuation

Slrukluneiialhäl

34

ochn-ZV \.

\ A

(80%)

\ A

COOCaI

(20%)

OCHN

(80%) --OCHN

W /

(20%)

/ J

--OCHN

c- / ~ S

N N

-H-C IH C-

\ AA /

N N

(70%) Wi

OCHN -f ] pSO ₂

NHCO-

Continuation of structural unit

(VIII) 44-

35

36

(75%)

- (- OCHN- / V-CONHNHC

(25%)

-HNOC

A- / YV-

CONH-

Tabel

Conditions in the manufacture of the membrane

') Parts by weight.

² ) Casting was carried out at room temperature on a glass plate using a doctor blade.

³ ) NMR = N-methylpyrrolidone.

Example no Polymer "p lot solvent lot Additive lot Pour
thickness dry Art 0.65 10 Art 87 Art 3 (° C / min) 25th (I) 0.66 10 NMP 87 LiCl 3 320 130
15th 26th (H) NMP LiCl 320 130
15th

37

38

continuation

Example No. Polymer

Type H ₁ ,

(111) 0.66

(IV) 0.69

(V)

(Vl)

0.65

0.55

(VII) 0.59

lot

10

15th

10

10

18th

Solvent additive

Type amount type amount

(VIII) 0.64

(IX) 0.62

(X)

(Xl)

0.64

NMP 87 NMP 79 NMP 87 NMP 87 NMP 75 NMP 80 NMP 90 NMP 86

0.55

21

73

LiCl

CaCI,

LiCI

LiCI

LiCI

CaCI ₂

LiCI

CaCI ₂

LiCl

Casting
dickc
(»Ρ) dry
(C'mini 350 125
17th 220 128
16 320 130
15th 320 130
15th 250 125
14th 300 130
15th 400 1.30
16 320 130
15th 250 130
15th

') Weight.

² ) Casting was carried out at room temperature on a glass plate using a doctor blade.

³ ) NMR = N-methylpyrrolidone.

Table 8 (continued) Characteristics of the membranes

Example no. salary*) Membrane- Conc pressure water ■ 100. water Salt return thickness tration of inflow permeability holding assets (%) Initial
solution**) 69.6 GO (%) (kg / cm ² ) (l / m ² / hour) (Wp) (%) 25th 55.7 73 1.0 80 38.2 530 95.7 26th 62.3 64 1.0 80 25.2 350 89.6 27 57.4 66 1.0 80 42.5 590 93.8 28 58.0 53 1.0 80 28.8 400 71.4 29 60.3 62 1.0 80 20.3 282 97.9 30th 65.9 65 1.0 80 13.5 187 99.1 31 71.0 74 3.5 100 24.3 325 98.8 32 51.0 85 1.0 80 41.2 570 94.5 33 61.5 48 0.5 80 17.8 235 98.6 34 50.3 62 1.0 80 21.3 296 92.4 35 • v ,,,. . weight
*) Water content = 71 1.0 80 13.2 183 99.5 of the water that is in the membrane is included

*) An aqueous NaCl solution was used as the starting solution.

Claims (2)

Patent claims: 1. Pcrmsclektiv polymeric membrane, characterized in that I. (I) the membrane consists essentially of a film-forming linear polymer which as main structural units repeating N-aryl-substituted benzimidazole units (A) of general formula (A-I) IO and or N N y \ / ν —C Ar. C— N N (A-2) Ar, Ar, contains where Y is a group —CONH— —NHCO- —CONHNHCO— —NHCONH— —NHCNHNHC— and or —C — NHNHCNH— Il Il oo denotes, m denotes zero or 1, Ar ₁ denotes an aromatic group with up to 15 carbon atoms which is trivalent in the formula AI and tetravalent in the formula A-2, the two nitrogen atoms in each ring to two adjacent core carbon atoms of the group Ar ₁ are bonded, and Ar ₂ and Ar _{3 are} monovalent aromatic groups with up to 15 carbon atoms, the units of the formulas AI and / or A-2 directly or via divalent organic groups (B), in which the average number of atoms excluding hydrogen atoms is not greater than 80, and wherein both ends of the groups (B) bonded to the units (A) are carbon atoms, are linked to each other; (2) the parameter H _{p of} the hydrophilic property, expressed by the following formula, of the linear polymer is at least 0.4: _{H =} W ₁₁ ^p Total number of atoms excluding hydrogen atoms in the polymer where N _{11 is} the number of hydrogen bonding units provided by the polar groups in the entire polymer and is expressed by the product of the number (N _A ) of hydrogen bonding groups in the entire polymer and their hydrogen bonding strength (Gk), and N ₁ means the number of ionic groups in the entire polymer provided that the number of ionic groups does not exceed 1 per 500 units of the molecular weight of the polymer; (3) the linear polymer in a solvent or solvent mixture, selected from Ν, Ν-dimethylacetamide, N-methylpyrrolidone, dimethylsulfoxide and / or hexamethylphosphoramide, which can optionally contain up to 5 weight percent lithium chloride, at 25 ⁰ C with formation of at least 7 weight percent Solution is soluble and II. The membrane is made from a solution which contains a) the linear polymer with an N-aryl-substituted benzimidazole structure and b) an aprotic polar organic solvent, which has the ability to linear Dissolve polymers in it, preferably together with c) a low molecular weight compound of not more than 500 present in the organic solvent b) and soluble in the following non-solvent d) is, by (1) the solution partially solidifies to such an extent that the partially solidified membrane obtained is self-supporting or has self-sustaining properties, and (2) the partially solidified membrane is immersed in a non-solvent d) for the linear polymer a) the one with the organic Solvent b) is compatible, at least 75 percent by weight of the organic Solvent b) or the organic solvent b) and the low molecular weight compound c) which are in the partial solidified membrane remain, can be extracted. 2. A method for producing a permselective polymeric membrane, characterized in that the membrane is produced from a solution which contains a) the linear polymer with an N-aryl-substituted benzimidazole structure and b) an aprotic polar solvent that has the ability to remove the linear polymer to dissolve in it, preferably together with c) a low molecular weight compound of not more than 500 present in the organic solvent b) and soluble in the following non-solvent d) is, by